Though he posted several tweets about the dagga, all used the same image, making it hard to estimate its exact size. But the multi-headed plant appears to be well over two metres tall with sturdy stems, and it is not entirely alone.

(Tito Mboweni, via Twitter)

Mboweni posted about the plant on 9 January, with a promise to push for the legalisation of dagga. He remains a firm proponent of full legalisation, with an eye to the tax revenue the SA government could claim from legal production.

On this one, the majority says: LEGALIZE IT!! I will put the proposal to legalize it at the Cabinet Lekgotla this January. The People have demanded it. But those medical doctors????. ???? pic.twitter.com/WGC78wsByC

"If he intends to sell it, then he's outside of the law. Presently, he's just posting photos of it and driving debate around whether it should be fully legalised for commercial use. I don't see that he prima facie falls foul of any laws," said Paul-Michael Keichel, a partner at Schindlers Attorneys who has been at the forefront of changes to the law.

Though Mboweni is showing off the plant in public, his farm remains a private space, Keichel said. "It's not like me posting a photo of my garden on social media turns it from a private space into a public one."